Emotion processing is a critical component of social functioning. Adults derive a considerable amount of emotion information from body posture and movement. In some circumstances, bodies are better sources of emotion cues than faces. Yet, virtually nothing is known about the development of emotion processing from body gestures. This is in contrast to a great number of studies that have examined facial emotion processing. The proposed studies are aimed at filling this gap. They will examine predictions from models of body knowledge development, emotion processing, and action understanding while documenting the nature of development in early infancy and examining mechanisms that drive development. Slaughter and Heron's model of body knowledge development proposes that visuospatial body knowledge is minimal early in life and slow to develop in comparison to facial knowledge. In contrast, other models of body knowledge development and theories of action understanding and emotion processing envision early development of knowledge about bodies and emotions signaled by them. One set of studies will contrast these predictions. Another set of studies will address a significant debate in the emotion literature concerning whether knowledge about basic categories of emotions is available early in life. A third set of proposed studies will test the hypothesis that visual exploration capacities contribute to the development of body emotion knowledge. Another group of studies will examine the proposition that motor experience and development are associated with body emotion knowledge development. The fifth set of proposed studies originates from empirical findings and theoretical propositions suggesting that learning plays a significant role in the development of object and social perception. We will test the hypothesis that body emotion knowledge development is facilitated by learning induced by observing exemplars of emotional behavior and correlations between bodily, facial, and vocal emotional expressions. Thus, the proposed studies will document the development of body emotion knowledge in infancy, examine the role of visual exploration as an underlying mechanism of development, and investigate whether motor development and observational learning contribute to this development. Many developmental disorders such as Autism are, at least in part, based on deficits in emotion processing. The proposed research will contribute to the analyses and treatment of such disorders by documenting the nature of emotion processing from body information in infancy and the manner in which it normally develops early in life.